Screw cutting machine



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OGRAPNING COMPANY TON. r:v c.

(No Model.) 3 Sheets-Sheet 2.

J. DAVIDSGHN. SCREW CUTTING MACHINE.

No. 510,329. Patented Dec. 5, 1893.

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SCREW CUTTING MACHINE. No. 510,329. Patented Dec. 5, 1893.

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7 UNITED STATES PATENT GFFIGE.

Jos'nrH DAvmsoHN, or BERLIN, GERMANY.

SCREW-CUTTING MACHINE.

SPECIFICATION forming part of Letters Patent No. 510,329, dated December 5, 1893.

Application filed July 30, 1892. Serial No. 441,763. (No model.) Patented in Germany June 22. 1892, No. 67,664; in France June 29,1892.No.222.691,andi11 England July 16.1892,N0.13,100.

dom of Prussia,Empire of Germany, have in vented certain new and useful Improvements in Screw-Cutting Machines, (for which I have obtained patents in Great Britain,No. 13,100, dated July 16, 1892; in France, No. 222,69l, dated June 29, 1892, and in Germany, No. 67,664, dated June 22, 1892,) of which the following is a full, clear, and exact specification.-

My invention relates to a screw cutting lathe which by means of a simple mechanism, permits the production of threads of different pitch, and right-handed screws as well as lefthanded ones. The mechanism by means of which this result is accomplished consists of a slide, which is displaced transversely to the main-spindle, from which it derives its movement, and is provided with an adjustable guide-bar effecting the lateral displacement of the slide-rest carrying the tool according to the angular position said guide-bar occupies in relation to the path of the slide. It will be obvious that by altering the position of this guide-bar the lateral displacement of the sliderest will be increased or decreased, and that this lateral displacement will be to the right or to the left according to the inclination of the guide-bar. Thus it will be apparent that right-handed and left-handed screws of different pitch may be cut on my improved lathe.

The main feature,however, of my newdevice consists in the arrangement of arod by means of which the slide on the guide bar and the slide rest for the tool are adj ustably connected with each other, and by which, further, the movement of the slide on the guide bar is transferred to said slide rest. By aid of this arrangement the distance between both slides may be altered according to any requirement and the tool may be directed to any part of the work piece independent of the position of the other slide. Finally, it is made possible by that arrangement to disengage the whole device, or even to remove it entirely from the lathe, so as to turn thereby the latter into a common lathe, which now, of course, may be used as such one.

My invention will be more readily understood by reference to the accompanying drawings, in which Figure -1 is a front elevation, and Fig. 2 a plan of my improved screw-cutting lathe, like letters denotinglike partsin both views. Fig. 3 is a front elevation of a part of the screwcutting lathe, drawn on a larger scale. Fig. 4 is a plan of the same parts, as in Fig. 3, also drawn on the larger scale.

The main spindle a is rotated in any usual manner, for instance by means of the cone b and a double geared fast head, as shown. The right half of the spindle a is supported in bushes g and the spindle is provided at its right end with the center 0, the face-plate c and the catch-pin 0 adapted to collide with the catch cZ fastened to the blank. The latter is held between the center 0, already mentioned, and the center 6 provided on the loose headf. Between the bushes g, the spindleo is provided with a worm h. A worm-wheel 2, Figs. 3 and 4, engages with the worm it; said worm-wheel is fixed to a vertical axle j, on the lower end whereof there is mounted a-sleeve j, to which are secured the change-wheels z" and 11 [or more change-wheels, if required]. The sleeve j may be locked in relation to the axlej by means of screws. 7

The part 20, Figs. 3 and 4, of the machine in which the axle j is journaled, may be displaced laterally, by means of slots w and screws 20 so that by suitable displacement of said part and by a vertical displacement of the sleeve j either of the toothed wheels t" i may be brought to engage with the rack It, provided on the transverse slide Z. During the lateral displacement of the axle j the worm wheel 2' remains meshing with the worm h, the length of the latter being sufficient for securing this result. It is obvious that when rotating the main spindle a, the worm h, worm wheel 2', and either of the change-wheels vi and i will effect a displacement of the slide Z, having the rack 70, transversely to the spindle a. The slide Z is guided in the gaunt-ree of the lathe, as shown at Z. Said slide is provided at its ends with plates m, each of which has a slot m. In the middle of the slide Z, or nearly so, is located the pivot 'n for the guidebar 0. The latter may be secured in various positions by means of screws and n'utso passing through the slots m. One of the plates m, or both as shown, are graduated, and the guide-bar 0 is provided with a corresponding sight and with a pointer 0 On the guide-bar glides the slide 13, composed of two parts, the upper of which may be turned in relation to the lower one; when adjusted, both parts may be secured to each other by means of screws 13 sliding in suitable slots. To the upper part of the slide 13 there is secured the boss 19, through which passes the guide-rod q; the screw rserves for locking the guide-rod q and the boss 1) in their relative positions.

At the right end of the guide-rod q there is secured the slide-rest s, carrying the tool 25, which is arranged in the usual manner. The slide-rest s glides in a guide .9. The left end of the guide-rod q is guided in a bearing a.

The operation of my improved screw-cutting lathe is as follows: First of all, the axle 7 is locked against lateral displacement in such a position, that eitherof the wheels '21 or t meshes with the rack is. Similarly the guide-bar 0 is secured by means of the screws 0' and the upper and lower part of the slide 19 by means of the screws 13 and finally the guide-rod q is. secured to the boss 19' by means of the screw 7'. The lathe may then be set in motion by rotating the main spindle a. The worm h, meshing with theworm-wheelt', efiects a rotation of the latter, of the axle j and the change-wheels t" and 6 One of these wheels engages with the rack is on the slide Z, and thus causes the latter to be displaced transversely to the main spindle a. During this displacement the slide p glides along the guide-bar 0, and the slide-rest s which is connected to the said slide 29 by means of the guide;r0d q is also displaced laterally more or less according to the angle of inclination of the guide-bar 0, the displacement being effected from the right to the left, when the guide-bar 0 is inclined to the left, whereas the displacement is effected in the opposite direction when the guide-bar 0 is inclined to the right [as shown in the drawings]. If the ratio between the worm h, the worm-wheel i, the change-wheels 2" i and the rack is known, it will be easy, by reading the number indicated on the scale by the pointer 0 to calculate the displacement of the slide 19 during one rotation of the main spindle Ct, that is to say, the pitch of the screw cut during this rotation. It will be obvious that by altering the position of the guide-bar o the lateral displacement of the slide p and consequently of the toolt will also be altered, so that screw-threads of very diiferent pitch may be cut by means of my improved machine. By the employment of change-wheels the limits within which these alterations of the pitch may be made are extended considerably.

Besides the advantage of permitting the production of left-handed and right-handed threads, as already mentioned, my improved screw-cutting lathe presents the further advantage, that the tool, after having been brought back to its initial position in order to cut the blank for a second time, passes exactly through the thread produced at the first cut. This is of particular importance when cutting screws of small pitch.

What I claim, and desire to secure by Letters Patent of the United States, is-

1. Ina screw cutting lathe: the combination of the slide restscarrying the tool 25, and of the adjustable guide-bar 0 carrying the slide 19, with a rod (1 arranged above the bed of the lathe, said rod connecting slide rest .9 with theslide p, for the purpose set forth.

2. In a screw cutting lathe: the combination of the slide rest .9 carrying the tool t, and of the adjustable guide-bar 0 carrying the slide 1), with a rod 1 arranged above the bed of the lathe, said rod adj ustably connecting slide rest 3 with slide 1) for the purpose set forth.

3. In a screw cutting lathe: the combination of the slide rest 3 carrying the tool 25, and of the adjustable guide-bar o carrying the slide 19, with a rod q arranged above the bed of the lathe, in front of, and parallel to, the spindle a, said rod connecting slide rest 3 with the slide p, for the purpose set forth.

4t. In a screw cutting lathe of the kind described: the combination, With the main spindle a and the worm h, of the Worm-Wheel '11, secured to the axle j, the change-Wheels 2" t secured to the sleeve j displaceable bearings of said axle being displaceable laterally, and of the slide Z, having rack 70, for the purpose set forth.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

JOSEPH DAVIDSOl-IN. \Vitnesses:

FR. SPERLING, R. HERPICI-I. 

